ONE OF THE MAJOR constraints, we are convinced, that keeps people from attempting do-it-yourself repairs or remodeling is the "house of cards" syndrome.
This phenomenon, which occurs all too frequently, turns the simplest-seeming fix into a homeowner's nightmare.
Basically, it means that touching any single part causes the entire structure to come tumbling down.
Karol encountered this when she decided to take the self-stick plastic covering off the bathroom walls just after she bought her current house.
The wallpaper stopped at a dropped ceiling, which she decided to get rid of, revealing gaps where water-laden plaster had fallen out, because the do-it-yourself glass shower doors directed all moisture from the tub to the ceiling and when the rest of the plaster was torn out, it revealed ancient knob-and-tube wiring that was positively dangerous.
She ended up with new walls, new ceiling, new wiring, new light fixture -- it was a big job, and not something she had intended to do before she had even moved in.
Now she'd like to remodel the bottom half of the room, but can't because well, because she has problems similar to the Baltimore reader who e-mailed a query about replacing her bathroom floor.
"I want to replace the small ceramic tile in my bathroom with large 12-inch tiles. I understand I will need more subfloor support for this. My questions are:
"What are the advantages/disadvantages to tiling over the original tile vs. ripping them out?
"I have mirrored accordion closet doors, which do not have much space under them. What can I do about these?"
The reader is probably right in figuring she'll need extra flooring support.
Ceramic tile is a rigid and unforgiving floor surface. The one thing it needs is a solid subfloor.
The tile will crack or come loose if there is any sort of bump or gap or spongy place underneath.
It's possible, at least in theory, to install new tile over old, using an old-fashioned method called "thick-set" -- basically an inch or so of mortar between the two layers.
However, the thick-set method raises the floor level and adds considerably to the weight.
It also requires some plumbing work, because the toilet flange has to be reset to match the new floor level.
Thick-set mortar is not something homeowners should attempt, and there may not be that many people still doing it professionally.
(Today's tile installation, thin-set, requires mortar that can be a little as 1/4 -inch thick -- a development that made it possible for novice tile installers to do a good job.)
If the old tile is vinyl, or even vinyl asbestos, you can usually nail plywood over it, creating a new underlayment on which to install ceramic tile.
Randy ran into a similar situation recently in a bath remodeling job.
He would have liked to tile over the existing tile, but there were several problems.
The old tile was installed with the thickset method, but a spongy spot around the heat vent in the floor indicated something was not right in the subfloor.
Randy decided to chip out the old tile, using a cold chisel and wearing safety goggles, and then had to chip out the old mortar the same way.
The sponginess turned out to be caused by a subfloor of 1/2 -inch plywood that was just not strong enough to support the mortar and tile of the old flooring.
Usually, houses are built with a 3/4 -inch plywood subfloor. In bathrooms and kitchens, or anywhere vinyl or ceramic tile is being installed, the subfloor is augmented with another layer of plywood, called the underlayment.
A lot of people use 1/4 -inch hardboard for the underlayment for vinyl, but we prefer 3/8 -inch plywood because it seems to hold nails better.
A ceramic-tile floor needs 1/2 -inch plywood glued to the subfloor and nailed in a 6-inch grid pattern.
Randy uses 8-penny flooring nails, rather than underlayment vTC nails, because they are more substantial and have a bigger thread to hold down better.
In his bathroom project, Randy glued and nailed 5/8 -inch tongue-and-groove plywood over the 1/2 -inch plywood, then added 3/8 -inch plywood underlayment.
The resulting 1 1/2 -inch surface provides a solid base for ceramic tile -- and builds the level back up to the toilet flange.
To answer the reader's question more directly, you really can't put new ceramic tile on top of old; you have to chip out the old tile.
And what you have to do to support the new tile will be determined by the extent and condition of the subfloor/underlayment.
If the old subfloor has no underlayment, or not enough to support the new tile, it will have to be augmented with more plywood.
This will raise the level of the floor -- possibly causing a problem with the mirrored doors.
The only solution would be to remove the doors and raise the doorway, so the doors could be reinstalled a bit higher. That would require a good bit of carpentry.
Or she could replace the doors with new, shorter ones, or with wooden doors that could be cut to fit.
Karol's bathroom also has tiny, ugly, ceramic tiles on the floor, and she'd love to replace them.
But that would mean raising the radiator (she has hot-water heat) and the toilet and -- and -- and -- and every time she contemplates the disruption to her only bath, she hears a little voice in her head warning, "Don't touch that card..."
Randy Johnson is a Baltimore home-improvement contractor. Karol Menzie is a feature writer for The Sun.
If you have questions, tips or experiences to share about working on houses, e-mail us at homeworlark.net, or write to us c/o HOMEWORK, The Sun, 501 N. Calvert St., Baltimore 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.
Pub Date: 12/01/96